A natural history program like this only comes along once every decade or so. It's been 10 years, in fact, since the first Planet Earth series gave a truly global view of the state of the world's ecosystems.

Planet Earth was the first natural history series to be filmed in high definition, captivating a global audience of more than half a billion people, and boasted stunning aerial footage shot from helicopters using gyro-stabilised cameras.

For the sequel, filmmakers are taking a more intimate approach to best make use of the new camera technologies that have developed over the past decade (including 4K resolution).

Drones and hand-held stabilisers allow cameras to get right in the thick of the action and up close and personal with everything from Komodo dragons to penguins, swimming sloths and elusive snow leopards.

You've likely already seen some amazing footage from the series thanks to another development of the past decade: social media.

The show's extended trailer has been viewed nearly 50million times on Facebook. Heart-stopping footage of a baby marine iguana narrowly avoiding dozens of snakes has been viewed more than four million times on Facebook.

"There's still quite a lot of debate about how much we should release in advance of the series," executive producer Mike Gunton tells me.

"If you're a traditional filmmaker then the worst thing is to give out spoilers, but the social media gurus say, no you want to put it out there. That's quite counterintuitive to a filmmaker. I thought, 'these (social media) guys know what they're doing, let them take this on'. It was the right call; they were dead right."

I had the pleasure of previewing the first two episodes of Planet Earth II and I can tell you that that viral clip of the baby iguana is just a taste of the amazing footage captured in the Galapagos Islands.